Noise reduction of food waste disposers



July 4, 1961 T. E. JENKINS NOISE REDUCTION OF FOOD WASTE DISPOSERS FiledMay 9, 1960 INVENTOR. VTHOMAS E. J'ENK\NS H 15 ATTORNEY United StatesPatent 2,991,018 NOISE REDUCTION OF FOOD WASTE DISPOSERS Thomas E.Jenkins, Louisville, Ky., assignor to General Electric Company, acorporation of New York Filed May 9, 1960, Ser. No. 27,778 4Claims. (Cl.241-1005) The present invention relates to food waste disposal apparatusof the type having an electrically driven unit adapted to be mountedbelow the drain opening of the kitchen sink for grinding and dischargingfood waste into a sewer system, and particularly to a means of reducingthe transmission of the noise generated by the disposer.

Several decades ago most kitchen sinks were manufactured of heavy castiron that was provided with a top porcelain coating. At the present timealmost all kitchen sinks are manufactured from thin sheet steel i.e.either cold rolled steel with a top porcelain coating or stainlesssteel. These sheet metal sinks are of relatively light gag metal andthey operate in the manner of a vibrating sounding board 'when a wastedisposer is mounted to the underside of the sink and large bones andother food Waste that are difficult to grind are handled by thedisposer. Recent design changes have tended to increase the grindingefiiciency and the power of the disposers while at the same time makingthe units more compact. All of these changes also make the unit noisierin operation.

The present invention relates to a mass loading means for deadening thetransmission of the noise of operating a food waste disposer supportedbeneath a kitchen sink.

Afurther object of the present invention is to provide a simple andinexpensive means for increasing the mass of a sheet metal sink.

A further object of the present invention is to provide a simple meansfor clamping a large heavy metal plate to the underside of a sheet metalsink that is adapted to support a food waste disposer to give the sinkthe effect of a cast iron sink insofar as noise transmission isconcerned.

The present invention relates to a food waste disposer for use with asheet metalsink. Such a sink includes a drain opening and there is ametal sleeve extending through the opening and supported therein. Thedisposer comprises a housing that includes a hopper, a grinding chamber,and a motor casing. The top of the hopper has an inlet opening forreceiving water and waste material. Clamping members are provided forhanging the disposer housing from the sleeve. These clamping membersinclude vertical adjusting screws which may be adjusted to hold a largerelatively heavy metal plate centered around the sleeve and stressedagainst the underside of the sink. Cushions or other suitable bearingmaterials may be compressed between the sink and the outer extremitiesof the plate remote from the sleeve. This plate functions to increasethe mass of the sheet metal sink thereby reducing vibrational noises inthe sink.

My invention will be better understood from the following descriptiontaken in connection with the accompanying drawing and its scope Will bepointed out in the appended claims.

FIGURE 1 is a top plan view of a portion of a kitchen counter showing asink mounted therein and a food waste disposer supported from the drainopening in a manner embodying the present invention.

and having a bottom wall 12 with a drain opening 13 below which a foodwaste disposer 14 may be supported as is seen in FIG. 2. Waste disposer14 includes a housing comprising a hopper 15, a grinding chamber 16, anda motor casing 17, reading from top to bottom. The top portion of thehopper 15 forms an inlet opening for receiving water and waste material.The hopper is fastened to the top of the grinding chamber 16 and thewaste will be delivered to the grinding chamber and shredded into fineparticles where it will be discharged through a sewer connection 18which is joined to a sewer line or septic tank system (not shown). Thedetails of the waste disposer are not specifically illustrated becausethis invention has general utility in this art and it is not limited toany particular design of waste disposer.

It will be observed that the housing of the waste disposer 14 has acircular top inlet opening aligned with the sink drain opening 13, andthat a metal sleeve 20 not only provides a passageway from the sink tothe interior of the disposer but also supports the disposer. The sleeve20 which is commonly referred to in the art as a sink flange is oftubular design with a large upper shoulder or flange 21 which is largerin diameter than the drain opening 13 so that the shoulder is hung fromthe bottom wall 12 of the sink thereby supporting the sleeve in thedrain opening. The lower edge of the sleeve 20 has an enlarged head 22as well as an inturned ledge or seat 23. This internal seat 23 supportsan annular rubber member 24 which serves as the support means for asuitable drain stopper 25.

A support ring 26 is formed by two semi-circular segments (not shown)which are fastened together at a point on the sleeve above the enlargedbead 22. Formed on the upper end of the disposer housing or hopper is anoutwar'dly projecting flange 28 which cooperates with a mounting ring 29that encircles the housing and extends within an annular groove 30 inthe throat of the hopper. Vertical adjusting screws 31 are threadedthrough the support ring 26 and are each provided with a nut 32positioned on the lower end thereof. Moreover the lower end of eachadjusting screw is provided with a screw driver slot 33 for turningthe'screws to obtain the necessary adjustment. The mounting ring 29 isprovided with a series of keyhole slots 34 (not shown in detail) so thatthe disposer housing can be hung from the nuts on the adjusting screws.

In order to assemble the disposer housing 14 to the sleeve 20, it isnecessary to raise the housing until the nuts 32 extend through thelargest portions of the keyhole slots of the mounting ring 29. Then byturning the disposer housing the mounting ring will be supported by thenuts 32. It is important that the adjusting screws 31 be raised to bearagainst the underside of the sink to prevent the disposer housing 14from rocking from its support. One other feature in the mounting meansis the use of a rubber gasket 35 between the support ring 26 and theupper flange 28 of the disposer housing in order to reduce thetransmission of noises from the disposer through the mount and into thesink. This mounting means of the disposer from the sleeve in the drainopening is illustrated in detail in'the Brezosky et al. Patent No.2,819,028 which is assigned to the same assignee as is the presentinvention. This mounting means is merely discussed in detail here forillustration purposes as one example of a suitable method of mounting,but it should not be considered as a limiting feature of the presentinvention.

The noise an appliance makes is becoming an increasingly importantproblem to the appliance engineer. Customers are now demanding that someappliances be quiet in operation and may in the future demand thatothers be much less noisy than they are at present by showing a markedpreference in their buying habits. Unfortunate- 1y, most kitchen sinksbeing installed today are sheet 7 metal sinks of relatively thin gage sothat the sink acts as a sounding board and reverberates whenever thefood waste disposer is set in operation grinding hard food waste such asbones and corn cobs.

The present invention teaches the use of a large and heavy metal plate40 which underlies the bottom wall 12 of the sink and is clamped againstthe sink to place the plate and sink under stress and increase theeffective mass a be fitted in centered relation over the sleeve 20 tobear against the underside of the sink wall 12. Rubber pads 42 may becompressed between the metal plate 40 and the sink wall 12 adjacent theouter extremities of the plate and at a distance outside the adjustingscrew means. These pads serve to insure firm bearing contact or pressurepoints between the plate and the sink wall and reduce the vibrationalnoises set up by the disposer during its operation. For instance, if onewere to knock his knuckles against the bottom wall 12 of the sheet metalsink, the resulting sound would be a dull thud. If the heavy plate 40were missing as in standard sink designs, then when a similar knockingtest is made the sound would be rather tinny and loud. A typical metalplate that may be used is a plate of hot rolled steel A thick, 10" wideand 12 long. Rubber pads 42 may be used as the bearing contact means ora putty-like material such as Duxseal may be used as an alternative totemporarily glue the plate to the underside of the sink until thevertical adjusting screws 31 can be raised in place to hold the platefirmly against the sink.

In certain prior art designs the vertical adjusting screws have beenprovided to bear against a clamping ring of nearly the same size as themounting ring 29. The applicants invention must be distinguished fromsuch a small clamping ring in that the metal plate 40 is large enough topartially cover the bottom wall of the sink as is seen in dotted linesin FIG. 1. Also the sink and the plate are clamped together understress. The plate 40 is heavy in weight to increase the mass of the sinkand substantially reduce the loudness of the noise.

In any eifective program of noise control one must be able to comparethe noise of present and previous models of appliances. This means thatnoise must be adequately defined and measured. Noise has many attributessuch as loudness, pitch, time distribution, direction, etc. All of thesefactors contribute to the annoyance factor of the noise. At presentthere can be an agreement by a jury of peers on the loudness, but not onits absolute annoyance factor. It is believed that loudness is one ofthe chief components of the annoyance factor and therefore loudnesswhich can be measured is the best index we have at present to comparethe annoyance factor and predict the possible reaction of the customerto the noise of an appliance. A phon is the unit of loudness level andit is numerically equal to the sound pressure level in decibels relativeto .0002 dyne/cm. of a 1,000 cycle pure tone which is judged by thelistener to be equivalent in loudness. Loudness, S is measured in soneswhile the loudness level P is measured in phons. These elements arerelated according to the equation By definition the loudness of a simpletone of 1,000 c.p.s. 40 decibels above .0002 microbar is l sone. Theloudness of a sound that is judged to be N times the 1 some tone is Nsones.

it has been our experience that if a food waste disposer is mounted inan old house having a cast iron sink the unit of loudness of the noisegenerated by the disposer is in the order of 26 sones. When this samedisposer is mounted in a sheet metal kitchen sink the loudness isbetween 110 and 120 sones. If elaborate precautions are taken, andspecial units are built with rubber hoppers, encapsulated motors, rubbersink mounts, rubber drain lines, and noise shields wrapped around thehousing, the noise level can be reduced to approximately 60 sones. Theuse of the present invention on sheet metal sinks noise level can bereduced to approximately 60 sones. down to an amount .of about 28 soneswhich is approximately the loudness when a cast iron kitchen sink isused. In other words the present invention removes the problem oftransmitted noise from a sheet metal sink as compared with a cast ironsink.

Modifications of this invention will occur to those skilled in this artand it is to be understood, therefore, that this invention is notlimited to the particular embodiment disclosed but that it is intendedto cover all modifications which are within the true spirit and scope ofthis invention as claimed.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Waste disposal apparatus for use with a sheet metal sink, saidapparatus comprising a housing enclosing a grinding chamber that has aninlet opening for water and Waste material at the upper end thereof, asheet metal sink, a sleeve adapted to be disposed in a drain opening ofthe sink, and clamping means for hanging the housing from said sleeve,said clamping means including a large relatively massive metal plateseveral times larger than the drain opening and centered around saidsleeve and vertical adjusting screw means adjustable to fasten thesleeve in the sink and hold said metal plate around the sleeve andagainst the underside of the sink, and cushions compressed between theunderside of the sink and the outer extremities of the plate at widelyspaced points remote from the said sleeve and at distances outside thevertical adjusting screw means to increase the mass of the sheet metalsink and reduce vibrational noises set up by said apparatus during itsoperation.

2. Waste disposal apparatus for mounting under a sheet metal sink, asink having a drain opening, a sleeve extending through the drainopening and supported therefrom, the disposal apparatus including ahousing that encloses a grinding chamber below a hopper that has aninlet opening for receiving water and waste material at the upper endthereof, and releasable means for clamping the upper end of said housingto the lower end of the sleeve; the invention comprising a largerelatively heavy metal plate adjacent the underside of the sink andbeing at least several times larger than the drain opening, adjustingmeans supported from the sleeve to clamp said plate to said underside ofsaid sink, and non-metallic means at the outer extremities of the platecompressed between the heavy metal plate and the underside of the sinkto form bearing points between the plate and the sink that are atdistances outside the said adjusting means, the heavy metal plate beingstressed against the bottom of the sink to add mass to the sheet metalsink and reduce the loudness of the noise created by the disposalapparatus and transmitted by the metal sink.

3. Means for clamping a large relatively heavy metal plate to theunderside of a sheet metal sink for reducing the noise level of thesink, a sheet metal sink having a drain opening, a sleeve extendingthrough said drain opening and supported therein, a waste disposalapparatus including a grinding chamber that has an inlet opening forreceiving water and waste material at the upper end thereof, and meansfor clamping the upper end of the disposal apparatus to the lower end ofsaid sleeve, said noise reducing means comprising a large relativelymassive metal plate at least several times larger than the drain openingand vertically adjustable means bearing upwardly from said disposalapparatus and engaging the said large plate for holding the platetightly against the underside of the sink, the metal plate covering asubstantial part of the underside of the sink and in eifect constitutinga part of the sink, the outer extremities of the plate having pressurepoints bearing against the underside of the sink at distances outsidethe said vertically adjustable means so as to increase the mass of thesink and reduce the tendency of the sheet metal to reverberate when thewaste disposal apparatus is in operation.

4. Means for mounting a large heavy metal plate against the underside ofa sheet metal sink as recited in claim 3 wherein the large metal platecovers a major portion of the underside of the sink and cushioningmaterial is positioned between the sink and the outer extremities of theplate at the said pressure points to prevent metal contact between theparts at these points and reduce vibrational noises set up by saidapparatus during its operation.

References Cited in the file of this patent UNITED STATES PATENTS PowersAug. 8, 1950 Brezosky et al. Ian. 7, 1958

